Guillain-Barré Syndrome (GBS) after Janssen 

COVID-19 Vaccine: 

Vaccine Adverse Event Reporting System (VAERS) 

Meeting of the Advisory Committee on Immunization Practices (ACIP)

July 22, 2021

Office of Biostatistics and Epidemiology (OBE)

FDA - Center for Biologics Evaluation and Research (CBER)
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Outline

• Vaccine Adverse Event Reporting System (VAERS)

• Preliminary reports of GBS after Janssen COVID-19 Vaccine

• Updated Janssen COVID-19 Vaccine EUA Fact Sheets

• Summary and Next Steps
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Strengths

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Rapidly detects potential safety 

problems

Potential detection of rare adverse 

events

Open-ended for hypothesis 

generation

Geographic diversity

Capability to monitor production 

lots

Limitations

Missing and/or inaccurate data

Reported diagnoses are not verified

Under-reporting 

Reporting bias (stimulated 

reporting)

Absence of unvaccinated control 

group 

Inability to assess causation

Not likely to detect long latency 

events

Vaccine Adverse Event Reporting System

• Passive surveillance of vaccines

• Nation’s early warning system for vaccine safety

• VAERS accepts all reports regardless of the plausibility of the vaccine causing 

the event or the clinical seriousness of the event
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Identifying preliminary VAERS reports 

of GBS after Janssen COVID-19 Vaccine

• Preliminary reports of GBS identified via:

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FDA medical officers daily review of incoming serious reports and/or

Automated query of VAERS for adverse event terms for GBS*

• Data Lock Point: June 30, 2021

• Further analysis is pending follow-up by VAERS program contractors for 

medical records, confirmation of diagnosis, and adjudication of each case 

using the Brighton case definition for GBS

*MedDRA PTs for query: acute polyneuropathy, autoimmune polyneuropathy, axonal and demyelinating polyneuropathy, 

demyelinating polyneuropathy, Guillain Barré syndrome, Miller Fisher syndrome. 
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Preliminary reports of GBS after Janssen 

COVID-19 Vaccine

COVID-19 Vaccine Total Serious Deaths

Janssen 100 95 1

Data Lock Point: June 30, 2021

Serious adverse events include death, life-threatening events, hospitalization, prolongation of hospitalization, 

congenital anomaly, significant disability, or otherwise medically important conditions.
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Characteristics n = 100

Sex a

Male 61 (61%)

Female 38 (38%)

Seriousness b

Serious 95 (95%)

Hospitalized 95 (95%)

Died 1 (1%)

Non-serious 5 (5%)

Overview of GBS reports after Janssen COVID-19 

Vaccine

a One report had missing age, sex, and onset information.

b Serious adverse events include death, life-threatening events, hospitalization, prolongation of hospitalization, 

congenital anomaly, significant disability, or otherwise medically important conditions.
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Characteristics

Age a

Median 57 years

Mean (standard deviation) 53.6 (12.46) years

Range 24 – 76 years

Number of reports with age 18 – 64 years 83 (83%)

Number of reports in with age ≥ 65 years 16 (16%)

Time to onset a

Median 13 days

Mean (standard deviation) 13.8 (9.80) days

Range 0 – 75 days

Number of cases in 21-day risk window 84 (84%)

Number of cases in 42-day risk window 98 (98%)

Overview of GBS reports after Janssen COVID-19 

Vaccine

a One report had missing age, sex, and onset information.
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Reports of GBS after Janssen COVID-19 vaccine: 

Selected Case Details 

• 95 (95%) patients were hospitalized

– 10 patients were intubated and/or required mechanical 

ventilation

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• 1 death

57-year-old man with past medical history of heart 

failure, stroke, hypertension, and diabetes mellitus 

presented with weakness 5 days post vaccination and 

was later hospitalized and died 25 days post vaccination 
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Reports of GBS after Janssen COVID-19 Vaccine: 

Selected Case Details 

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24 reports described bilateral facial paresis

12 reports described unilateral Bell’s palsy

6 reports mentioned a recent illness: generalized rash, 

upper respiratory infection, or flu-like symptoms 1-2 weeks 

before GBS

No reports listed concomitant vaccines
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Observed-to-expected (O/E) analysis assuming 42-day risk 

window

Age 

(years)

Cases Vaccine doses 

administered*

Personyears 

(PY)**

Background Rate 

per 100,000 

PY***

Expected 

Cases

Rate Ratio, 

95% CI

All Ages 

(18+ )

98 12,235,978 1295623 1.51 19.56 5.010 

(4.07; 6.11)

18 - <65 82 10,302,966 1090944 1.22 13.31 6.16

(4.90; 7.65)

65+ 16 1,933,012 204679.6 2.34 4.79 3.34

(1.91; 5.43)

* From CDC data as of 06/28/2021 

** Person-Years was based on number of vaccine doses administered within the age group; see slides 19 – 20 for statistical methods.

*** Sejvar JJ, Baughman AL, Wise M, Morgan OW. Population incidence of Guillain-Barré syndrome: a systematic review and meta-analysis. 

Neuroepidemiology. 2011;36(2):123-33. 
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O/E analysis assuming 42-day risk window

Age 

(years)

Cases Vaccine doses 

administered*

Personyears 

(PY)**

Background 

Rate per 

100,000 

PY***

Expected 

Cases

Rate Ratio, 95% 

CI

18 – 29 4 2,138,259 226412.5 0.88 1.99 2.01

(0.55; 5.14)

30 – 39 10 2,071,932 219389.4 1.07 2.348 4.26

(2.04; 7.83)

40 – 49 21 2,174,362 230235.3 1.29 2.97 7.07

(4.38; 10.81)

50 – 64 47 3,918,413 414906.6 1.63 6.76 6.95

(5.11; 9.24)

65+ 16 1,933,012 204679.6 2.34 4.79 3.34 

(1.91; 5.43)

* From CDC data as of 06/28/2021 

** Person- Years was based on number of vaccine doses administered within the age group; see slides 19 – 20 for statistical methods.

*** Sejvar JJ, Baughman AL, Wise M, Morgan OW. Population incidence of Guillain-Barré syndrome: a systematic review and metaanalysis. Neuroepidemiology. 2011;36(2):123-33. 
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Updated Janssen COVID-19 Vaccine 

EUA Fact Sheets

• July 12, 2021: Authorized EUA Fact Sheets were 

updated to include new information about GBS

EUA Fact Sheet for Healthcare Providers Administering Vaccine (Vaccination Providers)

5 WARNINGS AND PRECAUTIONS 

Subsection ‘5.3 Guillain-Barré Syndrome’ including the following information was added: 

Reports of adverse events following use of the Janssen COVID-19 Vaccine under 

emergency use authorization suggest an increased risk of Guillain-Barré syndrome during 

the 42 days following vaccination. 

Section 6 OVERALL SAFETY SUMMARY and subsection 6.2 Post Authorization Experience 

were also updated with information about GBS. 

EUA Fact Sheet for Recipients and Caregivers

Section on “WHAT ARE THE RISKS OF THE JANSSEN COVID-19 VACCINE?” was updated to 

include information under a new subsection entitled “Guillain Barré syndrome”
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Crude comparison with mRNA vaccines

COVID-19 

Vaccine

VAERS reports with 

GBS screening*

Doses administered Crude** VAERS GBS 

reporting rate per 

million doses 

administered

Janssen 100 12,235,978 8.1

Moderna 162 134,076,668 1.21

Pfizer-BioNTech 190 181,347,436 1.05

VAERS reports processed through June 30, 2021

Notes: 

Doses administered data per CDC Vaccination Report as of 7/1/2021

*GBS screening definition is any one of the following encoded MedDRA preferred terms: DEMYELINATING 

POLYNEUROPATHY;GUILLAIN-BARRE SYNDROME; MILLER FISHER SYNDROME. Include reports processed through 

7/1/2021.

**Counts of VAERS reports meeting GBS screening definition divided by doses administered; counts are based on 

encoded terms
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Reports of GBS after AstraZeneca 

COVID-19 Vaccine

• A total of 227 cases of GBS had been reported to 

EudraVigilance as of 27 June 2021, while around 51.4 million 

doses administered as of 20 June 2021

• EMA Pharmacovigilance Risk Assessment Committee (PRAC) 5 

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8 July 2021 meeting:

Recommended an update to the product information to include a 

warning for Guillain-Barre syndrome (GBS) reported following 

vaccination with AstraZeneca COVID-19 Vaccine

References: 

06 Public Safety Update_VAXZEVRIA_14 July 2021 (europa.eu)

Meeting highlights from the Pharmacovigilance Risk Assessment Committee (PRAC) 5-8 July 2021 | European Medicines 

Agency (europa.eu)
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Summary

• 100 preliminary reports of GBS after Janssen identified in VAERS as of 

June 30, 2021

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Observed reports > expected across multiple age groups, without respect 

to Brighton Collaboration criteria

Reporting rate for GBS is higher for Janssen than for mRNA vaccines

• July 12, 2021: Authorized EUA Fact Sheets were updated to include 

new information about GBS

• Next Steps

Obtain additional follow-up/medical records for Janssen reports

Evaluate Janssen reports to determine whether they meet the Brighton 

Collaboration case definition of GBS

Based on the number of confirmed cases, re-assess the observed-to- expected analysis for GBS after Janssen 

Follow up on updates from FDA Biologics Effectiveness and Safety 

System, the Center for Medicare and Medicaid Services databases, and 

the CDC Vaccine Safety Datalink active surveillance
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Acknowledgments

FDA - Center for Biologics Evaluation and Research (CBER)

Office of Biostatistics and Epidemiology (OBE) team:

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Jane Woo

Adamma Mba-Jonas

Rositsa Dimova

Meghna Alimchandani

Narayan Nair

Craig Zinderman

David Menschik 

Centers for Disease Control and Prevention